Python day1: first knowledge of Python

First, Python Introduction:

Python free, open source, object-oriented interpretation of the language, its syntax concise, in use without thinking about how to manage the underlying problems such as memory, and support in Linux,windows and other multi-platform operation, Python's standard library is very powerful, we just need to import it and call the methods therein, Can handle a variety of jobs, Python can also be embedded in the c\c++ program, Python is forced to indent the way the code is very readable, it is a reasonable combination of high performance and make programming simple and interesting features.

Python's main applications: Automated operations, automated testing, big data analytics, crawlers, web, and more.

The Python categories are divided into the following types:

Cpython: Compile with C, this is commonly used

Jyhton: Compiling python code into Java bytecode

IronPython: Python language implemented on net and mono

The Pypy:python implementation of Python, whose compilation execution process is the same as the C language's compilation execution (Python code-and machine code) executes faster, but is not mature enough to be used in production environments.

Second, comments and modules:

　　#: Single line comment

"" "" "" (or ""): Multiline Comment

Module Type:

Built-in modules, self-written modules, other modules written by others

Import module:

(1) Import module name

(2) From Module name Import method name

(3) Built-in function __import__ ()

SYS.ARGV Capture Parameters

Third, variable

Variable names are made up of letters, underscores, numbers, and numbers can be used as a starting point, and they can also have the same names as built-in keywords.

Memory consumption of variables:

　　

1 " Zhangsan " 2 " Lisi "

　　　

1 " Zhangsan " 2 name2 = name1

Iv. user interaction, entering characters

Raw_input (python2.7)

Input (python3.x)

Getpass: Implicitly entering content

Cases:　　　

1 Import Getpass 2 3 name = raw_input ("Pleaseinput username:")4 passwd = Getpass.getpass ("Please input passwd:")56  Print(name)7print(passwd)

V. Basic data types

1. Single value:

Digital

Integral type

Long integer type

Floating point Type

Plural

String:

‘‘

""

"" "" "" (or "" ")　　

Boolean value

true,1

false,0

2. Collection:

List

Meta-group

Dictionary

Collection (hash table)

Six, circulation

For

While

Python day1: first knowledge of Python